PC DB: Effect of Compress on System Used .KEY and .MBG Files

• Microsoft Mail for PC Networks, versions 3.2, 3.2a, and 3.5

SUMMARY

Maintenance of the version 3.x Microsoft Mail for PC Networks postoffices includes compressing of the user's mailbags, as shown on page 105 of the version 3.2 "Administrator's Guide" and page 107 of the version 3.5 "Administrator's Guide."

This compression will compress not only the user's mailbags but also the mailbags the mail system uses for the delivery of mail. Some examples are the INQUEUE3.MBG, <hex-id>.MBG for external postoffices, and SYSTEM.MBG.

MORE INFORMATION

Every mailbag contains a header for each mail message that is sent to a user. When the message is read or deleted, that header space is marked as free; however, the header is not actually deleted until a compress is run against the postoffice. Therefore, if you are using filesize to determine the amount of undelivered mail for a specific user, the count will be inaccurate unless a compress has been performed.

For example, if the MBG for a specific user is 5,452 bytes, the size would indicate there are 47 message headers in the .MBG (5452\116=47). However, if 40 of these messages have been moved into the .MMF, the MBG does not actually hold those 40 headers, and after a postoffice compress the mailbag will reflect a size of 812 (812\116=7).

For additional information, please see the following article in the Microsoft Knowledge Base:

   ARTICLE-ID: Q77926
   TITLE     : Description of Mail Database Subdirectories